Hey all, I've recently been fighting a lot with my lenses fogging while caving and was wondering weather anyone has any tips to deal with this. I usually content myself with just one lens with a UV filter (more to protect the lens then for anything else) when I go in, but I'm finding that the filter and the lens itself under the filter both fog and stay that way for the duration of our time underground. I am pretty nervous about trying to wipe the lens due to the amount of dirt/mud/crud that gets on everything when caving, so am trying to come up with any way to minimize fogging.

If there's fog between the filter and the lens, then there's moisture between them. I keep a UV filter on when I'm underground as well, same reason, lens protection. I keep a silicon desiccant pack in the filter case as well as in my camera case, in hopes of keeping them as dry as possible. Do you put the UV filter on prior to going underground? Keeping all the moisture out before putting the filter on should help with the fog on the main lens. As for the filter, I keep a microfiber pack towel (Sea to Summit), a small spray bottle of clean water, and a few lens cloths in my bag as well. If there's dirt or dust on the filter I give them a quick spray to dislodge what debris I can, dab with the microfiber towel and them finish it off with the lens cloth. If the filter gets scratched, I ditch it once I've gotten home and put on a new one before going back underground.

Fogging of the lens seems to occur primarily when there's A. a difference in temperature between your gear and the environment combined with B. high humidity. There's not a lot you can do about the humidity but I've had no problems taking pictures in extremely high humidity (Mexico, Guatemala etc.) as long as the camera is given time to adjust to the same temp as the cave. Keeping it in an insulated camera bag or pelican box is only going to make it take longer. It can also help if you pack some dessicant packs in your camera bag but really I've found just being patient and leaving the camera out of the bag for20-30 minutes is the best solution. This applies both if your going from an air conditioned building/vehicle to the cave in summer or a heated one in winter.Now if someone could come up with a solution to keep me from warming up my glasses and causing them to fog up I'd be happy. (I usually just have to put them in my camera bag :) )

Try Lasix surgery for the eyeglasses problem. I had it done 18 years ago (and had a touch-up three years ago). No glasses to fog -- whether in caves, on mountains, or even at home...you can just look at the alarm clock and see that it says 3:30 and roll over and go back to sleep without getting out of bed! Not as cheap as the de-fogging stuff they sell at every county fair (which does work). But it's always with you.

Thanks for the tips, guys! I usually leave my camera in a Pelican case until it's time to actually go into the cave so it's definitely in a different environment then that of the cave. I usually throw a dessicant in the camera bag as is, as well as bringing a microfiber for dirt and crud (although my hands are so dirty usually that I'm nervous about using it, haha). I'm heading out to do some caving this weekend, though, so I'll see if ya'lls tips help!

If your light is bright enough, you can also burn off some fog by blasting the lens with your headlamp. I do this with both camera and compass, especially near the entrance, where there is more moisture in the air.

GroundquestMSA wrote:If your light is bright enough, you can also burn off some fog by blasting the lens with your headlamp. I do this with both camera and compass, especially near the entrance, where there is more moisture in the air.

Sounds like a good idea, Jonah. I will have to try that next time my glasses fog up. Or my laser. Or my compass. My Zebralight gets pretty warm on high beam!

GroundquestMSA wrote:If your light is bright enough, you can also burn off some fog by blasting the lens with your headlamp. I do this with both camera and compass, especially near the entrance, where there is more moisture in the air.

Talk about tip of the day! Great idea, especially with the portable suns that pass as headlamps these days.